Light-sensitive supersensitized silver halide photographic emulsions

ABSTRACT

A supersensitized light-sensitive silver halide photographic emulsion is obtained by incorporating in the emulsion a combination of two specific dyes having the general formulas I and II as indicated below.

United States Patent Sato et al.

May 2, 1972 Inventors: Shui Sato, Hachioji-shi; Eiichi Sakamoto, Hanno-shi; Shizuo Saito; Kaiichiro Sakazume, both of Tokyo, all of Japan Konishiroku Photo Industry Co., Ltd., Chuo-ku, Tokyo, Japan Filed: June 9, 1969 Appl. No.: 831,714

[30] Foreign Application Priority Data Int. Cl ..G03c 1/14 Field of Search ..96/l04, I24, 100

References Cited UNITED STATES PATENTS 2,075,048 3/1937 Mees ..96/l04 3,522,052 7/1970 Shibaetal. ..96/l00 Primary Examiner-J. Travis Brown Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A supersensitized light-sensitive silver halide photographic emulsion is obtained by incorporating in the emulsion a combination of two specific dyes having the general formulas I and II as indicated below.

V4 =CH-(?=CH i (X V1 V m] R 3 I 3 Nr I R, in V1 I =CHC=CH- A I N l I (CHz)nSO I I 6 Claims, No Drawings LIGHT-SENSITIVE SUPERSENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSIONS This invention relates to light-sensitive silver halide photographic emulsions supersensitized by joint use of two or more of spectral sensitizing cyanine dyes.

The fact that addition of a certain cyanine dye is very effective for spectral sensitization of a photographic emulsion has been well known. Further, it has been known that use ofa dye which is different in its substructure from the above dye or a colorless organic compound in addition to the above dye remarkably improves spectral sensitivity of light-sensitive layer. This is called supersensitization and a number of combinations of sensitizing dyes have been proposed.

When the supersensitization is applied to a silver halide emulsion, it is desired that the following conditions are satisfied as well as improvement in spectral sensitivity:

l. Sensitized spectral region is proper.

, 2. Disadvantageous reaction with other additives in the emulsion is not caused and photographic properties stable to incubation of the emulsion and preservation of film are attained.

3. Color staining on film is not caused after development.

4. Fogging is not caused.

These conditions are particularly important when the supersensitization is applied to a red light-sensitive emulsion of a light-sensitive color photographic material. The sensitized spectral region of, for example, the red light-sensitive emulsion is preferably reduced in green light-sensitivity but increased in red light-sensitivity so that the best color reproduction may be obtained. Further, when a color coupler is added, it is required that no decrease in spectral sensitivity due to the reaction with said color coupler be caused. However, very few of the combinations among those known up to date satisfy the above conditions, in particular when they are added to color photographic material.

it is an object of this invention to provide a supetsensitized light-sensitive silver halide photographic emulsion wherein the above conditions are satisfied.

We found that use of a sensitizing cyanine dye shown by the general formula [I] or [ll] as given hereinafter in conjunction, or that is use of a sensitizingcyanine dye in which at least one anion radical such as carboxyalkyl group, sulfoalkyl group and a functional group derived therefrom is contained as a substituent at the heterocyclic nitrogen atom remarkably increased color sensitivity and the conditions as aforementioned were entirely satisfied.

In the above general formulas,

R,, R and R are each a lower alkyl group, hydroxyalkyl group, carboxyalkyl group, sulfoalkyl group or functional group derived therefrom with the proviso that at least one of R and R is carboxyalkyl group, sulfoalkyl group or a group derived therefrom; R and R are each a lower alkyl group;

V is a halogen atom, a lower alkyl group or alkoxy group;

V V: and V, are each a hydrogen atom, lower alkyl group, alkoxy group, and V, and V or V;, and V may form together a benzene ring or a ring including the methylenedioxy group;

o imisoi (a) s s :0 H (]3=CII- 70 on,-

\N on, M

l (l ll 75 ammo,-

1 Compounds shown by the general Formula II:

our,

cm, i

Any combination of at least, one compound of the general formula [I] and at least one compound of the general formula [ll] may be used in this invention.

' Such combination according to this invention fully satisfy the above conditions. The excellent effect of the combinations according to this invention is considered attributed to the presence of at least one anion radical such as carboxyalkyl group, sulfoalkyl group and a functional group derived therefrom at, the heterocyclic nitrogen atom in a sensitizing dye. When a known combination according to prior art in which no anionradical is contained as a substituent at the heterocyclic nitrogen atom, for example the combination described in U. S. Pat. No. 2,075,048 is used, color staining on a film is observed after development and disadvantageous reaction with other photographic additives readily occurs. In particular, when such known combination is used in color photographic material, spectral sensitivity in the presence of a color coupler is markedly decreased as time passes. According to this invention, such defects are overcome by introducing such anion radical as afore-mentioned as a substituent at the heterocyclic nitrogen atom.

The sensitive maximum wavelength of the light-sensitive silver halide photographic emulsion of this invention exists in the middle of sensitive maximum wavelengths of sensitizing dyes used alone, respectively. According to this invention, sensitization is possible over a broad wavelength region by varying the kind of sensitizing dyes and rate of amount to be added and therefore the most desirable sensitization is attainable in accordance with various purposes whether the sensitized emulsion is used for color photographic material or black and white photographic material. 7

Further, spectral sensitization of a panchromatic emulsion is possible according to this invention by increasing green light sensitivity by effecting the supersensitization with the addition of a pseudocyanine, merocyanine, oxacarbocyanine or benzimidazolocarbocyanine dye.

Sensitizing dyes used in this invention maybe added to silver halide photographic emulsion in the form of a solution in an organic solvent readily miscible with water such as methanol etc. and at any stage of the preparation of the emulsion. In general, the addition is preferably made just after completion of the second ripening. The amount of sensitizing dye to be added varies according to the kind of silver halide emulsion used, and it is generally suitable that the sum of the sensitizing dyes of the general formula [I] and the general formula [II] is 30-100 mg per kg of silver halide emulsion, where the sensitizing dye of the general. formula [II] is preferably 2,-70 percent of the total. The above limitation-on quantity and quantitative ratio of sensitizing dye is, however, not critical but variable. I I

The silver halide emulsion used in this invention may be any of silver 'iodobromide-, silver chlorobromido-, silver chloroiodide', silver bromideand silver chloride emulsions. These emulsions may be sensitized by a chemical sensitizer such as a noble metal-, sulfur-, reductionor polyalkylene oxide sensitizer and ordinary additives such as stabilizer, surfactant, hardening agent, etc. may be added to the emulsions. Further, a hydrophilic or oleophilic cyan coupler of incorporated type which forms cyan color may be contained in the emulsions.

Now, the present invention will be illustrated by way of the following several examples, which are given only with a view to explaining this invention but not limiting the present invention thereto.

EXAMPLE 1 A silver iodobromide emulsion containing 5 mol of silver iodide which has been treated with gelatin coagulant is subjected to the second ripening according to the ordinary manner. Immediately after completion of the second ripening, a 0.1 percent methanol solution of the sensitizing dyes of the general formulas [I] and [II] is added in the amount indicated in the Table I per kg of the emulsion. The emulsion thus treated is coated on a film supported and dried.

The resulting light-sensitive photographic material is exposed to light by means of a sensitometer KS-l (manufactured and sold by'Konishiroku Photo Industry Co., Ltd.) at Lux, 5400K, and thereafter treated with the developing solution having the following formulation for 5 minutes at 20C.:

Metol 3 g Anhydrous sodium sulfite 50 g Hydroquinone 6 g Sodium carbonate (monohydrate) 29.5 g Potassium bromide l g TABLE 1 Thereafter, fixing, bleaching and further fixing are effected in sensitizing dye and its amount the ordinary manner to give a cyan negative image.

P of emulsion) Relative As to the samples thus obtained, measurements on density, sensitizing dye sensitizing dye speed to max, relative speed to green light or red light and fog are made. The Formula [I] of Formula [II] red light FOE (ml) results obtained are shown in Table 2.

(1) 30 72 0.04 655 (1) 50 122 0.04 235 TABLE 2 (11) 5 0. 04 0 (ll) 50 13( 0. 0a 390 EEEY E (1) (11) 20 M5 Sensitiziii d d g ye an its amount Green Red (1) 45 (u) 5 162 04 665 10 (mg. per kg. of emulsion) light light Fog 4 50 37 0.05 651 1 (Cmmonm if 13) 10 55 0 04 600 21 100 (13) 50 12s 0 04 090 3 62 (4) 40 (13) 10 5 184 0 04 672 5 84 4) 45 (13) 5 159 0 04 663 6 107 24 150 0.08 3 30 71 0. 03 654 5O n 0. 8 25 14 i 0 7) 25 (13) 25 2 0. 5 7 40 1a) 10 172 0 05 674 g 15 160 0. 0. 4 (0) 30 136 0.08 677 v 0) 50 150 0. 04 677 g 122 B: 0 43 (13) 2 100 0. 04 680 7 163 (I 05 0) 45 13) 5 211 0. 04 681 262 07 v 20 253 0. 07 In the Table 1, each number in the parentheses denotes the corresponding compound listed hereinbefore.

As shown in the table, spectral sensitivity of the supersen- 25 sitized emulsion according to this invention is remarkably int creased as compared with the case where each sensitizing dye From F above table, appareni that of is used alone. Further, it will be noted that the emulsion can be senmzmg y accordmg to F1115 Invention effecnve for sensitized over a broad wavelength region by varying the increasing relative speed to red light even in the presence of sitizing dye used and its amount. Thus, the most desirable the color mcol'poratfafl f p as compared with the spectral sensitization is attainable in accordance with various comwlcombmauon ofihe sensitizing dyes and purposes whether the sensitized emulsion is used for color or Further from 'f relatlfe Speed to green llghtv black and white photographic materiap noted that the combination according to the PIESCI'lblnVfil'lIIOIl remarkably increases relative speed to red light, without the EXAMPLE 2 3 5 increase of relative speed to green light. Such combination of sensitizing dyes is one desirable or sensitizing red light-sensitive emulsion of color photographic material and excellent color reproduction is attainable.

A high-speed silver iodobromide emulsion containing 5 mol of silver iodide is produced according to the neutral method. Immediately after completion of the second ripening, 0.l percent methanol solution of the sensitizing dyes of the general-formulas [l] and [II] is added to the emulsion in the amount indicated in the Table 2 per kg of the emulsion. EXAMPLE3 Thereafter, the color coupler, N-octadecyl-l-hydroxy-Z-- naphthoamido-4-sulfonic acid sodium salt is dispersed in the To 1 kg of the-neutral high-speed silver iodobromide emull i i h di mannerand H i dj md to 6,8, sion same as that used in Example 2 is added 0.1% methanol The emul ion thus reated i oated on a film u port and solution of the sensitizing dyes of the general formulas [l] and dried to give a red light-sensitive color photographic material. [ll] in the amount indicated in the Table 3. Further, the color On the other hand, a control sample is prepared by using the coupler, l-octadecyl-2-[2-( l-hydroxy)naphthyl]- sensitizing dyes of U.S..Pat. No. 2,075,048 under the same benzimidazolo-S-sulfonic acid is added in the ordinary manner conditions as above. 5 and pH is adjusted to 6.8 to give red light-sensitive color The sensitizing dyes used in the control sample are as folphotographic emulsion. lows: A part of the resulting emulsion is immediately coated on a (A) S film support and the other part is coated on a film support after incubation at 40 C. for 3 hours. A control sample is prepared by using the same control sensitizing dyes as used in Example 2 under the same condition as above. Cam The resultin sam les are then s b'ected to th ex 0 u t 1 g p u e p 5 re 0 I light and development in the same manner as in Example 2.

3 Results of measurement on density are shown in Table 3. S S (B) v l Z I TABLE 3 I 2H5 C0ated aiter l l i l C t .1. met. iia ter 2H5 2H5 ti aly Jitter hours after I" the addition the addition h tographic materials'are then exposed to 921222812 EEIBLCEBEL The resultin 0 light and treate d with the developing solution having the folfgff fi fgmfi ei ig :83:38 3 8 2 lowing formulation for 10 minutes at 20C. in the same of emulsion) red light Fog red light Fog mam'ler as Example 11 Control (A) 25 (B) 25 0.07 51 0. 07 N,N-Diethyl-p-phenylenediamine sulfate I g Do (A) 40 (B) 10 )4 0.06 46 0.07

drous sodium sulfite carbonate (monohydrate) 82.0: g Pot ssium bromide s 0 40 (13) 10 148 0. 00 0.00

Watertomakeup ll 75 0)47 (11) 3 22.10.07 210 0.07

'As apparent from Table 3,the combination of the control sensitizing dyes (A) and (B) in which no anion radical is contained as substituent at the heterocyclic nitrogen atom causes an outstanding decrease in relative speed to red light after the incubation in the presence of the color former, whereas the combination according to the present invention causes little decrease in the relative speed even in the presence of the color former. This is considered as resulting from the presence of at least one anion radical such as the sulfoalkyl group and carboxyalkyl group at the heterocyclic nitrogen atom of the sensitizing dye. It will be understood therefore that the combination according to this invention is particularly suitable for supersensitization I of Y the red light-sensitive emulsion of color photographic material.

EXAMPLE 4 A light-sensitive silver iodobromide reversal color photographic emulsion containing 3 mol of silver iodide and sensitized by goldand sulfur-sensitization is subjected to the second ripening. Immediately after completion of the second ripening, 0.1% methanol solution of the sensitizing dyes of the general formulas [l] and [ll] is added to the emulsion in the amount indicated in Table 4 per kg of the emulsion. Further, to the emulsion is added the color coupler, 4-chloro-l-hydroxy-Z-N-octylnaphthoamide dissolved in di-n-butyl phthalate by heating and dispersed in gelatin solution by using sodium alkylbenzenesulfonate. Thereafter, pH is adjusted to 6.8. The emulsion thus treated is coated on a film support and dried to give red light-sensitive reversal color photographic material. The control is prepared by repeating the above procedure using the control sensitizing dyes as used in Example 3.

The samples thus obtained are then'exposed to light in the same manner as Example 3 and treated with a first developing solution having the following formulation for 10 minutes at 20C.:

Metol Sodium sulfite (anhydrous) 5 Hydroquinone Sodium carbonate (monohydrate) 4 Potassium bromide Potassium thiocyanate Water to make up I 1 After the usual stopping, hardening and washing with water, the samples are subjected to a second exposure to white light and development at 20C. for minutes using a color developing solution having the following formulation:

N-Ethyl-N fi-methanesulfonamido-ethyl-3-methylaminoaniline sulfate 5.0 g Sodium sulfite (anhydrous) 2.0 g Sodium carbonate (monohydrate) 50 g Potassium bromide 1.0 g Benzylalcohol 3.8 g Sodium hydroxide 5.5 g

Water to make up l I Then, the usual stopping, fixing, washing with water and bleaching are effected. The photographic materials thus treated are washed with running water for minutes and dried. Measurement on density is made as to the samples to give the results as shown in Table 4.

TABLE 4 The results shown in the table indicate that the light-sensitive silver halide photographic emulsion of this invention possesses superior sensitivity to the prior emulsions even in the presence of the oleophilic color former of incorporated type.

5 What we claim is:

l. A light-sensitive silver halide photographic emulsion, characterized by containing at least one sensitizing cyanine dye of the general formula [I] in combination with at least one sensitizing cyanine dye of the general formula [ll] R R and R are each a lower alkyl group, hydroxyalkyl group, carboxyalkyl group, or sulfoalkyl group with the proviso that at least one 'of R and R is a carboxyalkyl group or sulfoalkyl group,

R and R are each a lower alkyl group;

V is a halogen atom, lower alkyl group or alkoxy group;

V V and V are each a hydrogen atom, lower alkyl group or alkoxy group. and V and V or V,, and V may form together a benzene ring or a ring including methylenedioxy group;

X is an anion;

n is 2 or 3 and m is l or 2.

2. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further comprising a color coupler.

3. A light-sensitive silver halide color, photographic emulsion as claimed in claim 1, wherein said emulsion has been sensitized by way of noble metal sensitizers, sulfur sensitizers, reduction sensitizers or polyalkylene oxide type sensitizers.

4. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further including stabilizers, surface active agents, coating aids or hardeners.

5. A light-sensitive silver halide color photographic material which comprises a film support and, coated thereon, a layer of the emulsion as claimed in claim 1.

6. A light-sensitive silver halide color photographic emulsion as in claim 1 wherein the dye of general formula l is I (CH2)3SO3H ((IJIIQ)3SO3 and the dye of general Formula. II is 

2. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further comprising a color coupler.
 3. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, wherein said emulsion has been sensitized by way of noble metal sensitizers, sulfur sensitizers, reduction sensitizers or polyalkylene oxide type sensitizers.
 4. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further including stabilizers, surface active agents, coating aids or hardeners.
 5. A light-sensitive silver halide color photographic material which comprises a film support and, coated thereon, a layer of the emulsion as claimed in claim
 1. 6. A light-sensitive silver halide color photographic emulsion as in claim 1 wherein the dye of general formula I is 